The invention relates to a fastener with a shoulder that is insertable into a mounting space in a hollow structure and is rotational within the hollow structure such that a grip member grips mounting extensions on opposite sides of the hollow structure from behind and from within and having at least one stop member that makes contact with the front external edges of longitudinal walls of the hollow structure abutting the mounting space and is connected with the grip member and further is elastically mounted relative to the grip member by a spring biased element acting perpendicular to the stop member.
Fasteners of this type are used in the fastening of objects, for example, to a C-shaped mounting rail. To this end, the mounting rail can be fastened to a base structure. The fastener is introduced into the mounting space and, for example, rotated 90xc2x0. The fastener thus grips the holding projections of the mounting rails. In an initial fixed position it is possible to displace the fastener along the length of the mounting rail for the purpose of making adjustments. To effect a final fixed position of the fastener to the mounting rail, the grip member is biased relative to the stop by using a threaded pin or bolt, and it thus securely clamps to the mounting projections. This type of fastener is suited for fastening elongated objects such as tubes or the like.
A fastener of this type, for example, is disclosed in DE 197 36 933 A1. This well-known fastener having a bolt is characterized by a grip member that is rotational such that the grip member grips the mounting projections arranged on the mounting rails. The mounting projections of the mounting rails are fixable, using a nut element, between the grip member and a moveably mounted stop member situated axial to the bolt. To facilitate an initial fixed position a pre-stressed spring element is arranged between the nut and the stop. The spring has the effect that the grip member is drawn up against the stop by the spring force and the mounting projections are lightly clamped between the grip member and the stop. In particular, the well-known fastener is initially fixed to the mounting rail. By moving the fastener along the mounting rail, its position can be adjusted. The position of the fastener relative to the mounting rail is secured by tightening the nut element on the bolt. In this situation, the nut assumes the function of the spring element and fixes the mounting projections of the mounting rail between the stop and the grip member.
The advantage of this known solution is that the adjustment can be made in the case of the initially fixed fastener. By application of a force opposing the resilient force of the spring on the bolt, the initial fixed position is loosened and the fastener can be adjusted along the length of the mounting rail. If the force acting upon the bolt is removed, the fastener is again in the pre-set or initial position in the mounting rail.
The disadvantage of the known solution resides in the fact that the xe2x80x98hammer headxe2x80x99, following introduction into the mounting space of the mounting rail, must be rotated by an angle certain, for example 90xc2x0, using the bolt, in order to optimally grip the mounting projections from behind. Particularly in difficult to reach places, this circumstance becomes a disadvantage, because a user has no opportunity of inspection for the purpose of determining whether the xe2x80x98hammer headxe2x80x99 is rotated to the pre-determined angle relative to the holding projections. In the case of fasteners that are under dynamic loading, this situation alone can result in failure of the fastener between the mounting rail and the known fastener.
The object of the present invention is to provide a fastener with a rotational grip member that allows a pre-fixed position that assures proper positioning of the grip member relative to the holding projections. Further, the fastener is manageable and allows for simple assembly.
According to the invention, the object is achieved in that the stop is characterized by a coupling part and the grip member is characterized by a counter-coupling part, such parts being connectable with each other to form a detachable, rotationally resistant connection.
In that the stop and the grip member are coupled to one another, the possible positions of the grip member relative to the mounting projections are pre-determined; in particular, the angle between the stop and the grip member is set. That means that for a user, the position of the grip member in the coupled condition is unequivocal. It is critical that the stop is essentially rotationally-locked relative to the mounting rail, especially relative to the holding projections, so that a definite positioning of the grip member can be assured. For example, an object to be fixed, in particular a bracket element, serves as the stop.
Preferably the coupling is characterized by pawls and grooves that act together in a form-locking fashion and can be positioned, by relative movement perpendicular to the stop, between a release position and at least one engagement position, whereby the coupling in the passive state is held in an engagement position by means of the spring element. The result is that, in the release position, it is possible for the user to place the coupling between various coupling positions, in particular to set different angles between the grip member and the mounting space. In a preferred embodiment the coupling is of a cylindrical design, wherein the axis of the coupling runs approximately centrally to the width of the mounting space and perpendicular to the stop. In this case, the width is defined as the extension transverse to the length of the mounting rail opening.
The coupling advantageously exhibits at least two engagement positions, an entry or introduction position and a locked position, whereby the distance (a) between the stop and the grip member in the entry position corresponds at least to the extension (b) of the holding projections perpendicular to the stop and in the locked position greater than the extension (b). It is thus possible, in the entry position of the coupling, for the user to pass the fastener through the mounting space of the mounting rail and by placement of the coupling in the release position and by rotating to set the grip member in the gripping position. Once the predetermined position of the grip member relative to the holding projections is reached, the locked position can again be connected. In a preferred embodiment the coupling exhibits two engagement positions, an entry position and a locked position. In this way, handling is especially simplified for the user. The locked position is defined in such a manner relative to the mounting rail opening, in particular relative to the holding projections, that fixing of the grip member is optimal, particularly the gripped surface is maximized. Preferably the coupling is characterized by two diametrically arranged pawls that engage form-lockingly in the locked position into two complementarily formed locking grooves and in the entry position into two entry grooves whereby the entry grooves receive the pawls only partially. The fact that the entry grooves receive the pawls only partially allows positioning of the coupling from the entry position into the release position with only a minimum application of force. In particular, the spring biasing element and the entry grooves are so constructed that the pawls can be repositioned from the entry position into the release position by mere rotation. From such position a torque moment is sufficient to position the coupling in the entry position into which it snaps on its own by virtue of the spring force. A particularly advantageous embodiment exhibits webs between the locking grooves and the entry grooves with a pitch that is so dimensioned that the pawls slide out of the release position into the entry position. A pitch of, for example, 30xc2x0 has been shown to be particularly advantageous. Of course, the pitch can be designed greater, since the sliding behavior is dependent upon different base conditions such as spring force and/or material.
Preferably, the grip member is connected to the stop by a bolt, whereby the grip element is connected frictionally or in a force-locking manner and the stop is rotationally connected with the bolt. The bolt has at the end facing away from the grip member a torque transmission means, which projects at least partially radially over the grip member. It is thus possible for the user, by using the bolt, to bring both the torque to a positioning between the various entry positions and the force perpendicular to the stop for positioning between the release position and the entry position. In addition, the frictional or force-locking connection between the bolt and the grip member assures simple and manageable mounting of the fastener. At the start of the fastening operation the coupling is situated in the entry position. In such position the fastener is guided by the user into the mounting rail opening up to the stop that frontally outward abuts the edges of the hollow structure longitudinal walls lining the mounting space. By the application of torque to the torque transmission means the pawls are drawn out of the entry grooves. In a particular embodiment the entry grooves are further characterized by a V-shaped design. The webs present between the entry grooves and the locking grooves guide the pawls axially to the bolt. The pawls snap in a form-locking manner into the locking grooves and the rotational movement of the grip member is blocked. The fastener is pre-fixed in the locking position with the mounting rail. This means that the grip member optimally grips the holding edges. The frictional or force-locking connection between bolt and grip member is embodied in such a fashion that it releases and the bolt is screwed by the torque moment into the grip member. Since the torque transmission means overlaps the bolt at least partially radially and is particularly embodied as a screw head, the result is a secure clamping to the mounting rail, in particular to the holding projections, between the stop and the grip member, because the stop is compressed by the torque transmission means axially to the bolt against the grip member.
The spring biasing element is advantageously embodied as an annular conical washer that is arranged on the side of the stop facing outwardly from the rear grip member, in order to configure the spring element in a space saving and economical way.
In another preferred embodiment, the spring biasing element is designed as a cylindrical coil spring arranged on the side of the stop facing outwardly from the grip member, in order to assure economical manufacture.
Preferably, the spring biasing element is formed as a plastic part that is arranged on the side of the stop facing outwardly from the grip member, to allow the least possible expansion of the fastener outside of the hollow structure.
The distance axial to the bolt between the rear grip member and the stop advantageously corresponds at a maximum to the height of the holding projections axial to the bolt. Thus, it is assured that the holding projections between the grip member and the stop can be firmly clamped.
The stop and the grip member advantageously each exhibit a sleeve-like guide member, it being possible to bring such members into engagement, in order to assure guidance of the rear grip member relative to the stop. Preferably the two guide parts can be slid into each other, having a common middle axis, and are constructed rotationally relative to each other. In the case of this further embodiment the two guide parts are arranged advantageously in the region of the coupling, in order to assure proper function of same.